Hereinafter, the present invention will be described with reference to the embodiments of the invention, but the following embodiments do not limit the invention according to the claims. In addition, not all the combinations of the features described in the embodiments are essential to the solution of the invention.
FIG. 1 is a schematic perspective view showing the appearance of the spatial light modulator 100. FIG. The spatial light modulator 100 has a substrate 210 and a reflective portion 240.
The plurality of reflective portions 240 are two-dimensionally arranged on the substrate 210 to form a matrix. Each of the reflectors 240 has a square reflective surface of a size of several micrometers to several hundreds of micrometers and forms a part of the spatial light modulation device 200 which swings individually with respect to the substrate 210.
As shown in the figure, when the reflective portion 240 reflects light to the spatial light modulator 100 in a tilted state due to different shaking, the reflected light has an illuminance distribution. Therefore, by controlling the oscillation of the reflecting portion 240, it is possible to form various illuminance distributions in the reflected light.
2 is a perspective view showing a single spatial light modulation device 200 taken out. The spatial light modulation device 200 has a structure in which two layers are stacked on a substrate 210.
The lower side of the structure on the substrate 210 has a shield 220 that includes a shield plate 222 and struts 224. The shielding plate 222 is disposed along four sides of the spatial light modulation element 200. The struts 224 support the shielding plate 222 on the substrate 210. As a result, the shielding plate 222 is fixed to the substrate 210 in a state surrounding the spatial light modulation device 200, and is electrically connected to the adjacent spatial light modulation device 200 in the spatial light modulator 100 To prevent interference.
1, a plurality of spatial light modulators 200 are disposed adjacent to each other, a shielding plate 222 is provided between the adjacent reflection parts 240, Can be blocked. Thus, heating of the substrate 210 by the irradiation light can be suppressed.
The upper side of the structure on the substrate 210 has a reflective portion 240 including a support layer 242, a reflective layer 244, and a movable electrode 246. The support layer 242 has a flat surface on the upper surface in the figure, and supports the reflection layer 244. The movable electrode 246 is disposed on the lower surface of the support layer 242 in the figure. The reflective portion 240 is supported from the substrate 210 to be freely swingable with respect to the substrate 210 as a whole.
3 is a schematic exploded perspective view showing a structure of the spatial light modulation device 200. As shown in Fig. 1 and 2, the same reference numerals are assigned to common elements, and redundant explanations are omitted.
The spatial light modulation device 200 includes a substrate 210, a shielding portion 220, a load portion 230, and a reflection portion 240. The shield 220 and the luggage compartment 230 are fixed to the upper surface of the substrate 210. The reflection portion 240 is attached to the load-bearing portion 230.
On the substrate 210, two pairs of fixed electrodes 212 and 214 having the same shape are disposed. The substrate 210 is formed of, for example, a silicon single crystal and includes a CMOS circuit for supplying driving power to the fixed electrodes 212 and 214. [ The fixed electrodes 212 and 214 are formed of a conductive material such as a metal and disposed symmetrically with respect to the center of the substrate 210 in parallel with the four sides of the substrate 210.
The shielding portion 220 has a shielding plate 222 disposed along four sides of the substrate 210 and a strut 224 supporting the shielding plate 222. The shielding plate 222 is disposed along the four sides of the substrate 210, outside the region where the fixed electrodes 212 and 214 are disposed. The pillars 224 are disposed on four corners of the substrate 210 on the surface of the substrate 210 on the outer side of the region where the fixed electrodes 212 and 214 are disposed.
The substrate 210 in the spatial light modulation device 200 is a part of the substrate 210 on which the spatial light modulator 100 is formed. The substrate 210 does not have the shape as shown but when the single spatial light modulation device 200 is focused on, the shape of the substrate 210, which the spatial light modulation device 200 occupies, As shown in the drawing, the reflecting portion 240 is a rectangle slightly larger than the reflecting portion 240.
The load part 230 has a column 232, a stationary frame 234, a movable frame 236 and a swinging part 238. The load part 230 is a part of the region of the substrate 210 on which the fixed electrodes 212 and 214 are disposed Respectively. The post 232 secures the stationary frame 234 to the substrate 210 at the four corners of the luggage compartment 230 itself.
The movable frame 236 is disposed inside the fixed frame 234 concentrically with the fixed frame 234 and is coupled to the fixed frame 234 by a torsion shaft portion 235. [ The movable frame 236 rocks with respect to the fixed frame 234 due to the elastic twist deformation of the twisted shaft portion 235.
The swinging portion 238 is disposed inside the movable frame 236 concentrically with the fixed frame 234 and the movable frame 236 and is coupled to the movable frame 236 by the swinging shaft portion 237. The oscillating portion 238 oscillates with respect to the movable frame 236 due to the elastic twist deformation of the warping shaft portion 237. [ The oscillation portion 238 can be tilted in an arbitrary direction with respect to the substrate 210 by combining the oscillation of the movable frame 236 itself and the oscillation of the oscillation portion 238 with respect to the movable frame 236 have.
Also, the oscillating portion 238 rocks due to the elastic deformation of the warping shafts 235 and 237. A warp shaft portion 235 for swinging the movable frame 236 with respect to the fixed frame 234 and a warp shaft portion 237 for swinging the oscillating portion 238 with respect to the movable frame 236 are made of the same material, And are formed to have the same dimensions. As a result, the load when the oscillating portion 238 is oscillated is stabilized, and the controllability of the spatial light modulation device 200 is improved.
The reflector 240 has a support 248 at the center of the lower surface of the supporting layer 242 provided with the movable electrode 246. The lower end of the strut 248 coupled to the support layer 242 at the top is coupled to the oscillating portion 238 of the luggage compartment 230. As a result, the reflective portion 240 can be supported on the substrate 210 in a state in which the reflective portion 240 can be tilted in an arbitrary direction with respect to the substrate 210.
In addition, in the spatial light modulation device 200, the gimbal portion 230 is disposed at the same height as the shielding portion 220 with respect to the substrate 210. Therefore, when the spatial light modulation device 200 is manufactured by lithography, the luggage compartment 230 and the shielding compartment 220 can be formed in parallel.
It is preferable that the shielding portion 220 is formed by a conductor for the purpose of providing an electromagnetic shielding function and the gimbal portion 230 is formed for the purpose of electrically connecting the circuit on the substrate 210 and the movable electrode. Therefore, it is preferable that the shielding portion 220 and the luggage compartment portion 230 are made of a conductive material such as a metal such as a TiAl alloy.
On the other hand, it is preferable that the supporting layer 242 of the reflecting portion 240 has a high rigidity and a light weight. Therefore, it can be formed of, for example, an oxide, a nitride, or a carbide which is bulked as a thin film. Further, the support layer 242 may be formed of amorphous silicon. Amorphous silicon can form a thick thin film at a low temperature, so that it is possible to form the support layer 242 which is light in weight and high in flexural rigidity without damaging the existing structure.
The reflective layer 244 can be formed of a metal film, a dielectric multilayer film or the like laminated on the support layer 242 as a thin film. In the case of forming the reflective layer 244, the surface of the support layer 242, which is a base, may be mirror-polished beforehand and planarized with high accuracy.
The movable electrode 246 can be formed of a conductive material such as a metal. When the support layer 242 is formed of amorphous silicon, the movable electrode 246 itself can be used as the movable electrode 246. However, by forming the movable electrode 246 with metal, it is possible to further improve the electrical characteristics of the electrode have. By using the movable electrode 246 made of metal, the thermal stress causing the bending of the reflection portion 240 can be balanced by the front and back of the support layer 242, and the deformation of the reflection portion 240 can be suppressed have.
4 is a schematic sectional view of the spatial light modulation device 200, and shows a cross section taken along the line A-A shown in Fig. The same reference numerals are assigned to elements common to those in Fig. 3, and redundant explanations are omitted.
On the substrate 210 of the spatial light modulation device 200, the shielding plate 222 is disposed on the edge side of the fixed electrode 214. The gimbal portion 230 is disposed closer to the center of the substrate 210 than the fixed electrode 214.
Therefore, the shielding plate 222, the fixed frame 234, the movable frame 236, and the like are not overlapped with the fixed electrode 214 in the direction perpendicular to the substrate 210. As a result, the fixed electrode 214 is opposed to the movable electrode 246 located on the upper side in the figure on the whole surface.
5 is a schematic cross-sectional view of the spatial light modulation device 200 and shows a state in which drive power is supplied to one side of the fixed electrode 214 located on the left side of the drawing in the same cross section as in Fig. An electrostatic force is applied between the fixed electrode 214 and the movable electrode 246 to which the driving power is applied and the reflective portion 240 is pulled toward the fixed electrode 214 together with the movable electrode 246. As a result, the warp shaft portion 235 is deformed, and the reflecting portion 240 swings overall.
6 is a schematic cross-sectional view of the spatial light modulation device 200, and shows a B-B cross section shown in Fig. The same reference numerals are assigned to elements common to those in Fig. 3, and redundant explanations are omitted.
The shielding plate 222 is disposed on the edge side of the fixed electrode 212 on the substrate 210 of the spatial light modulation device 200. The gimbal portion 230 is disposed closer to the center of the substrate 210 than the fixed electrode 212.
Therefore, the shielding plate 222, the fixed frame 234, the movable frame 236, and the like are not overlapped with the fixed electrode 212 in the direction perpendicular to the substrate 210. As a result, the fixed electrode 212 is opposed to the movable electrode 246 located at the upper side in the figure at the front face.
7 is a schematic cross-sectional view of the spatial light modulation device 200 and shows a state in which drive power is supplied to one of the fixed electrodes 212 located on the left side of the drawing in the same cross section as in Fig. An electrostatic force is applied between the fixed electrode 212 and the movable electrode 246 to which the driving power is applied and the reflective portion 240 is pulled toward the fixed electrode 214 together with the movable electrode 246. As a result, the warp shaft portion 237 is deformed, and the reflecting portion 240 swings overall.
As described above, in the spatial light modulation device 200, by applying drive power to one of the fixed electrodes 212 and 214, the reflection portion 240 can be oscillated. The inclination direction of the reflecting portion 240 can be arbitrarily changed by applying driving power to the pair of fixed electrodes 212 and 214 adjacent to each other among the fixed electrodes 212 and 214 at the same time. Thus, the spatial light modulation device 200 can electrically control the inclination of the reflection layer 244 of the reflection portion 240 with respect to the substrate 210.
The distance between the fixed electrodes 212 and 214 and the movable electrode 246 in the spatial light modulation device 200 driven by the electrostatic force is made wider than the gap between the fixed electrodes 212 and 214 and the movable electrode 246, Is fixed on the fixed electrodes 212 and 214 side. In the spatial light modulation device 200, since the movable electrode 246 is disposed on the lower surface of the reflection portion 240 remote from the substrate 210, the margin until the pull-in phenomenon occurs is large. In other words, the range in which the reflective portion 240 can be swung without increasing the pull-in phenomenon is widened.
In the spatial light modulation device 200, each of the warp shafts 235 and 237 is disposed outside the electric field formed between the fixed electrodes 212 and 214 and the movable electrode 246. Therefore, the influence of the static electricity on the twist axis portions 235 and 237 is suppressed, and the movable frame 236, the oscillating portion 238, and the reflecting portion 240, which are suspended from the twist axis portions 235 and 237, (Pulled down) due to the presence of the ink.
Since the spatial light modulation device 200 drives the reflection portion 240 by the fixed electrodes 212 and 214 disposed in the vicinity of the outer edge of the substrate 210, The reflecting portion 240 can be driven more efficiently by the driving power. In addition, since the fixed electrodes 212 and 214 having the same shape and area are symmetrically arranged, the driving conditions of the fixed electrodes 212 and 214 are the same, and the reflective portion 240 can be driven with good controllability .
Referring back to FIG. 1, in the spatial light modulator 100, the slopes of the plurality of reflection parts 240 can be individually controlled by controlling the driving power applied to the individual spatial light modulation device 200 have. In addition, in the individual spatial light modulation device 200, the shielding part 220 blocks the electromagnetic mutual interference with the adjacent other spatial light modulation device 200, so that the operation of the individual spatial light modulation device 200 Stable. Therefore, since an arbitrary irradiation pattern can be formed by reflecting the light onto the spatial light modulator 100, the spatial light modulator 100 can be used as a variable light source, an exposure apparatus, an image display apparatus, an optical switch, and the like.
8 to 24 are sectional views showing a manufacturing process of the spatial light modulation device 200.
8 to 23 are drawn by the cross section shown by the arrow C in Fig. The fixed electrodes 212 and 214 on the substrate 210 and the gimbals 230 on the substrate 210 are shown in the cross-section shown in these figures, although the shields 220 and the struts 224 and 232 of the load- The twisted shafts 235 and 237 are not shown.
8 to 22 show a manufacturing process, corresponding elements of the spatial light modulation device 200 may be included in a shape different from that shown in Fig. Therefore, in each drawing showing the fabrication process, each element is given a unique reference numeral, and in FIG. 23, at the stage when the spatial light modulation element 200 is completed, the correspondence relationship with elements of the spatial light modulation element 200 .
First, as shown in Fig. 8, a flat substrate 210 is prepared. As the material of the substrate 210, a member having a flat surface such as a compound semiconductor substrate, a ceramic substrate, or the like can be widely used besides a silicon single crystal substrate.
It is assumed that a CMOS circuit for supplying driving power to the fixed electrodes 212 and 214 is already formed on the substrate 210. [ It is assumed that the fixed electrodes 212 and 214, which are not shown on the C-C cross section, are already formed on the substrate 210.
The fixed electrodes 212 and 214 can be formed by depositing a metal such as aluminum or copper on the substrate 210 by physical vapor deposition, chemical vapor deposition, plating, or the like. The metal layer deposited on the substrate 210 can be patterned into the shape of the fixed electrodes 212 and 214 using a resist.
9, a resist material is deposited to a thickness at which the fixed electrodes 212 and 214 are buried, and the first sacrificial layer 311 is formed on the substrate 210. Then, as shown in FIG. The thickness of the first sacrificial layer 311 corresponds to the height of the shields 220 of the spatial light modulation device 200 and the supports 224 and 232 of the load part 230. The first sacrificial layer 311 can be formed by applying a resist material by a spin coat, a spray coat, or the like and pre-baking. As a result, the surface of the substrate 210 is planarized.
Subsequently, as shown in Fig. 10, the first sacrificial layer 311 is patterned. The first sacrificial layer 311 can be patterned by sequentially performing exposure, development, and pre-baking on the applied resist material. The resist material may be processed by a dry etching method such as plasma etching.
By the patterning, the first sacrificial layer 311 is provided with a contact hole 321 penetrating to the surface of the substrate 210. The contact hole 321 is formed in a region where the shielding portion 220 and the pillars 224 and 232 of the load-bearing portion 230 are disposed.
11, a first metal layer 331, which is a part of the pillars 224 and 232 of the shielding portion 220 and the luggage compartment portion 230, is formed by depositing a metal to fill the contact hole 321. Then, Is formed. The first metal layer 331 can be formed by depositing a metal material such as TiAl alloy by physical vapor deposition, chemical vapor deposition, plating, or the like.
Next, as shown in Fig. 12, a second metal layer 332 is formed on the entire surface of the first metal layer 331 and the first sacrifice layer 311. Then, as shown in Fig. The second metal layer 332 can be formed by depositing a metal material such as TiAl alloy by physical vapor deposition, chemical vapor deposition, plating, or the like.
Subsequently, as shown in FIG. 13, the second metal layer 332 is patterned. As the method of patterning the second metal layer 332, various dry etching or wet etching can be appropriately selected. In this way, the pattern of the existing first metal layer 331 is increased, and the shielding plate 222 not shown in the cross section is formed.
Next, as shown in Fig. 14, the second sacrificial layer 312 is deposited on the surface of the first sacrificial layer 311 exposed between the remaining second metal layers 332, and the entire surface is planarized. The second sacrificial layer 312 may also be formed by applying a resist material by spin coating, spray coating or the like and pre-baking.
15, metal is deposited on the entire surfaces of the second metal layer 332 and the second sacrificial layer 312 and the metal is deposited on the entire surfaces of the fixed frame 234, the movable frame 236, A third metal layer 333 serving as a swinging part 238 is formed. The third metal layer 333 can be formed by depositing a metal material such as TiAl alloy by physical vapor deposition, chemical vapor deposition, plating, or the like.
Subsequently, as shown in Fig. 16, the third metal layer 333 is patterned. As a result, the fixed frame 234, the movable frame 236, and the oscillating portion 238 of the luggage compartment 230 are formed. As the patterning method of the third metal layer 333, various kinds of dry etching or wet etching can be appropriately selected.
17, the entire surface of the third metal layer 333 and the second sacrificial layer 312 is planarized by the third sacrificial layer 313. Then, as shown in Fig. The third sacrificial layer 313 may also be formed by applying a resist material by spin coating, spray coating or the like and pre-baking.
The thickness of the third sacrificial layer 313 above the third metal layer 333 corresponds to the height of the strut 248 in the reflective portion 240 of the spatial light modulation device 200. [ Therefore, the third sacrificial layer 313 is deposited thicker than the third metal layer 333, and the third metal layer 333 is embedded in the third sacrificial layer 313.
18, the third sacrificial layer 313 is patterned to form a contact hole 322 reaching the top surface of the third metal layer 333. The contact hole 322 is provided in a region where the strut 248 of the reflection portion 240 of the spatial light modulation device 200 is formed. The third sacrificial layer 313 may be patterned by a dry etching method such as plasma etching.
19, metal is deposited on the surface of the third sacrificial layer 313, the entire inner surface and the bottom surface of the contact hole 322, and the metal is deposited on the movable electrode 246 of the reflecting portion 240 A fourth metal layer 334 is formed. The fourth metal layer 334 can be formed by depositing a metal material such as TiAl alloy by physical vapor deposition, chemical vapor deposition, plating, or the like.
20, an amorphous silicon layer 340 serving as a support layer 242 of the reflection portion 240 is deposited on the entirety of the fourth metal layer 334. Then, as shown in Fig. The method of forming the amorphous silicon layer 340 can be selected from various physical vapor deposition methods and chemical vapor deposition methods. Since the contact hole 322 formed in the third sacrificial layer 313 is deep, a depression may be formed on the surface of the amorphous silicon layer 340 to match the shape of the contact hole 322. [
21, a reflective film 350 serving as a reflective layer 244 is formed on the entire surface of the amorphous silicon layer 340. [ The reflective film 350 may be formed of a metal material. The reflective film 350 may be formed of a dielectric multilayer film. The method of forming the reflective film 350 can be selected from various physical vapor deposition methods and chemical vapor deposition methods.
The surface of the amorphous silicon layer 340 may be mirror-polished before the reflection film 350 is formed. Thus, the flatness of the surface of the reflective film 350 can be improved, and the reflectance of the reflective film 350 can be improved.
Subsequently, as shown in Fig. 22, the fourth metal layer 334, the amorphous silicon layer 340, and the reflective film 350 are collectively trimmed. The trimming can suitably use a dry etching method such as plasma etching. As a result, the surface of the third sacrificial layer 313 is exposed in the vicinity of the edge of the fourth metal layer 334.
Next, as shown in Fig. 23, the sacrificial layer from the third sacrificial layer 313 to the first sacrificial layer 311 is removed, and the spatial light modulation element 200 is completed. Since the sacrificial layer from the third sacrificial layer 313 to the first sacrificial layer 311 is directly or indirectly continuous, it can be collectively removed by etching using gas or liquid.
In the spatial light modulation device 200 manufactured through the above process, the movable electrode 246 is electrically coupled to the surface of the substrate 210 through the metal spool 230. Thus, through the circuit on the substrate 210, the movable electrode 246 is coupled to a reference voltage, e.g., a ground potential. As a result, a stable electric field can be formed between the movable electrode 246 and the fixed electrodes 212 and 214 to which the driving power is applied.
Further, in the spatial light modulation device 200, a metal shielding portion 220 is formed on the substrate 210 itself. Thus, the shield 220 is coupled through a circuit on the substrate 210 to a reference voltage, e.g., a ground potential. As a result, the shielding portion 220 can effectively prevent the intrusion of electromagnetic waves from the outside, and also shields the emission of electromagnetic waves from the spatial light modulation device 200 itself to the outside. Therefore, in the spatial light modulator 100 in which many spatial light modulating elements 200 are disposed adjacent to each other, the operation of the individual spatial light modulating elements 200 is stabilized.
In the spatial light modulation device 200, since the movable electrode 246 is disposed on the lower surface of the reflection portion 240 remote from the substrate 210, the margin until the pull-in phenomenon occurs is large. Therefore, the distance between the fixed electrodes 212 and 214 and the movable electrode 246 may not be increased by increasing the thickness of the sacrificial layer.
As a result, it is possible to avoid a crack or the like which is caused when the sacrifice layer is thickened, and the process risk can be reduced. In addition, since the height of the swinging reflecting portion 240 does not need to be made too large, an increase in displacement of the reflecting portion 240 with respect to the plane direction of the substrate 210 can be suppressed. Therefore, when a plurality of the spatial light modulation devices 200 are arranged in the spatial light modulator 100, it is possible to fill the space between the adjacent spatial light modulation devices 200 and improve the aperture ratio of the spatial light modulator 100 .
23, before the step of removing the first sacrificial layer 311, the second sacrificial layer 312 and the third sacrificial layer 313 shown in FIG. 23, the surface of the reflective film 350 A mirror polishing step may be introduced. As a result, the reflectance of the reflective film 350 can be further improved.
Also, the manufacturing process of the single spatial light modulation device 200 has been described. However, a plurality of the spatial light modulation devices 200 may be manufactured simultaneously on one substrate 210. A plurality of spatial light modulators 200 are fabricated on a single substrate 210 and then diced for each substrate 210 to form a spatial light modulator 100 having a plurality of spatial light modulators 200 ) Can be manufactured coaxially. As a result, productivity can be improved and the spatial light modulator 100 can be supplied at low cost.
Figs. 24 to 30 show a manufacturing process of another spatial light modulation device 201. Fig. In these figures, the same reference numerals are given to elements common to the manufacturing process of the spatial light modulation device 200, and redundant explanations are omitted.
The steps described with reference to FIGS. 8 to 18 for the spatial light modulation device 200 are common to the manufacturing process of the spatial light modulation device 201. FIG. Thus, Fig. 24 shows the successive steps to the step shown in Fig.
24, the surface of the third sacrificial layer 313 provided with the contact hole 322 and the surface of the third metal layer (not shown) formed in the contact hole 322 are exposed in the process of manufacturing the spatial light modulation device 201, 333 are deposited on the entire surface of the substrate. As a result, a fifth metal layer 335, which is a part of the column 248 of the reflecting portion 240, is formed.
The fifth metal layer 335 is formed without being interrupted at the side wall of the contact hole 322. In other words, the fifth metal layer 335 is deposited until the thickness of the fifth metal layer 335 becomes uninterrupted even in the upright portions in the side walls of the contact holes 322.
The fifth metal layer 335 can be formed by depositing a metal material such as TiAl alloy by physical vapor deposition, chemical vapor deposition, plating, or the like. The fifth metal layer 335 is called " fifth " for the purpose of distinguishing it from other metal layers of ejection, and does not mean that it is formed later than the fourth metal layer 334 described later.
25, the fifth metal layer 335 is patterned, and portions other than the inside and the periphery of the contact hole 322 are removed. As the patterning method of the fifth metal layer 335, various dry etching or wet etching can be appropriately selected.
26, a metal is deposited on the entire surfaces of the third sacrificial layer 313 and the fifth metal layer 335, and a fourth metal layer (not shown) serving as the movable electrode 246 of the reflector 240 334 are formed. The fourth metal layer 334 can be formed, for example, by depositing a metal material such as TiAl alloy by physical vapor deposition, chemical vapor deposition, plating, or the like. The film thickness of the fourth metal layer 334 is thinner than that of the fifth metal layer 335.
27, an amorphous silicon layer 340 serving as a support layer 242 of the reflection portion 240 is deposited on the entirety of the fourth metal layer 334. Then, as shown in Fig. The method of forming the amorphous silicon layer 340 can be selected from various physical vapor deposition methods and chemical vapor deposition methods.
The fifth metal layer 335 protrudes from the third sacrificial layer 313 and the fifth metal layer 335, which are the underlying layers of the amorphous silicon layer 340. Therefore, the surface of the amorphous silicon layer 340 may slightly protrude from the upper portion of the fifth metal layer 335 in the figure.
Next, as shown in Fig. 28, a reflective film 350, which is a reflective layer 244, is formed on the entire surface of the amorphous silicon layer 340. As shown in Fig. When a part of the amorphous silicon layer 340 rises, the ridge of the amorphous silicon layer 340 is repeated on the surface of the reflective film 350 as well.
The reflective film 350 may be formed of a metal material. The reflective film 350 may be formed of a dielectric multilayer film. The method of forming the reflective film 350 can be selected from various physical vapor deposition methods and chemical vapor deposition methods.
The surface of the amorphous silicon layer 340 may be mirror-polished before the reflection film 350 is formed. Thus, the flatness of the surface of the reflective film 350 can be improved, and the reflectance of the reflective film 350 can be improved.
Subsequently, as shown in Fig. 29, the fourth metal layer 334, the amorphous silicon layer 340, and the reflective film 350 are collectively trimmed. The trimming can suitably use a dry etching method such as plasma etching. As a result, the surface of the third sacrificial layer 313 is exposed in the vicinity of the edge of the fourth metal layer 334.
Next, as shown in Fig. 30, the sacrificial layer from the third sacrificial layer 313 to the first sacrificial layer 311 is removed, and the spatial light modulation element 201 is completed. Since the sacrificial layer from the third sacrificial layer 313 to the first sacrificial layer 311 is directly or indirectly continuous, it can be collectively removed by etching using gas or liquid.
In the spatial light modulation device 201 manufactured through the above process, the movable electrode 246 is coupled to the gimbal portion 230 via the fifth metal layer 335 forming part of the strut 248. The fifth metal layer 335 has a film thickness larger than the film thickness of the fourth metal layer 334 forming the movable electrode 246 and is formed without being interrupted at the side wall of the column 248 .
Accordingly, in the spatial light modulation device 201, the movable electrode 246 and the luggage compartment 230 are electrically coupled with each other securely. Further, the electric resistance in the column 248 is also low, and the electric potentials of the movable electrode 246 and the luggage compartment 230 become the same. As a result, the electrical characteristics of the spatial light modulation device 201 are stabilized, and the controllability is improved.
Since the contact hole 322 in the case of forming the pillars 248 can be buried by the fifth metal layer 335, the surface of the amorphous silicon layer 340, which is not to be deposited on the reflective film 350, do. Therefore, the flatness of the reflective film 350 is improved, and the effective aperture ratio as the spatial light modulation device 201 is increased.
Figs. 31 to 36 show a manufacturing process of another spatial light modulation device 202. Fig. In these drawings, elements common to the spatial light modulation elements 200 and 201 are denoted by the same reference numerals, and redundant explanations are omitted. The steps described with reference to FIG. 8 to FIG. 18 for the spatial light modulation device 200 are common to the manufacturing process of the spatial light modulation device 202. Thus, FIG. 31 shows a step that continues to the step shown in FIG.
In the manufacturing process of the spatial light modulation device 202, a metal material is deposited in the contact hole 322 formed in the third sacrificial layer 313, as shown in Fig. As a result, a sixth metal layer 336 having a thickness equal to the film thickness of the third sacrificial layer 313 and serving as a column 248 of the reflection portion 240 in the spatial light modulation element 202 is formed .
The sixth metal layer 336 can be formed by depositing a metal material such as TiAl alloy by physical vapor deposition, chemical vapor deposition, plating, or the like. The sixth metal layer 336 is referred to as " sixth " for the purpose of distinguishing it from the fourth metal layer 334 and the fifth metal layer 335 which are exposed and formed later than the fourth metal layer 334 It does not mean anything.
32, a metal is deposited on the entire surfaces of the third sacrificial layer 313 and the fifth metal layer 335 to form a fourth metal layer 334 to be the movable electrode 246. [ The fourth metal layer 334 can be formed by depositing a metal material such as a TiAl alloy by physical vapor deposition, chemical vapor deposition, plating, or the like.
Next, as shown in Fig. 33, an amorphous silicon layer 340 to be a support layer 242 is deposited on the entirety of the fourth metal layer 334. The method of forming the amorphous silicon layer 340 can be selected from various physical vapor deposition methods and chemical vapor deposition methods.
The surfaces of the third sacrificial layer 313 and the sixth metal layer 336 which are not formed on the amorphous silicon layer 340 are substantially flat although the surface of the sixth metal layer 336 The surface of the amorphous silicon layer 340 may slightly protrude from the upper side.
Next, as shown in Fig. 34, a reflection film 350 serving as a reflection layer 244 is formed on the entire surface of the amorphous silicon layer 340. [ When a part of the amorphous silicon layer 340 rises, the ridge of the amorphous silicon layer 340 is repeated on the surface of the reflective film 350 as well.
The reflective film 350 may be formed of a metal material. Further, the reflective film 350 may be formed by a dielectric multilayer film. The method of forming the reflective film 350 can be selected from various physical vapor deposition methods and chemical vapor deposition methods. Further, the surface of the amorphous silicon layer 340 may be mirror-polished before the reflective film 350 is formed. Thus, the flatness of the surface of the reflective film 350 can be improved, and the reflectance of the reflective film 350 can be improved.
Subsequently, as shown in Fig. 35, the fourth metal layer 334, the amorphous silicon layer 340, and the reflective film 350 are collectively trimmed. The trimming can suitably use a dry etching method such as plasma etching. As a result, the surface of the third sacrificial layer 313 is exposed in the vicinity of the edge of the fourth metal layer 334.
36, the sacrificial layer from the third sacrificial layer 313 to the first sacrificial layer 311 is removed, and the spatial light modulation element 202 is completed. Since the sacrificial layer from the third sacrificial layer 313 to the first sacrificial layer 311 is directly or indirectly continuous, it can be collectively removed by etching using gas or liquid.
In the spatial light modulation device 202 manufactured through the above process, the movable electrode 246 is coupled to the gimbal portion 230 via the sixth metal layer 336 forming the strut 248. Here, since the support 248 is formed entirely of metal, the movable electrode 246 and the luggage compartment 230 are electrically coupled with each other.
Further, the electric resistance in the column 248 is also low, and a potential difference is not easily generated between the movable electrode 246 and the luggage compartment 230. [ As a result, the electrical characteristics of the spatial light modulation element 202 are stabilized and the controllability is improved.
Further, since the film formation of the amorphous silicon layer 340 is flat, the surface of the reflective film 350 becomes flat. Therefore, the flatness of the reflective film 350 is improved, and the effective aperture ratio as the spatial light modulation element 202 is improved.
37 to 41 show a manufacturing process of another spatial light modulation device 203. FIG. In these drawings, the same reference numerals are given to elements common to the manufacturing process of the spatial light modulation device 200, and duplicate descriptions are omitted.
The steps described with reference to FIG. 8 to FIG. 19 for the spatial light modulation device 200 are common to the manufacturing process of the spatial light modulation device 203. Thus, Fig. 37 shows the successive steps to the step shown in Fig.
In the manufacturing process of the spatial light modulation device 203, a high-concentration p-type layer 344 is formed by being laminated on the fourth metal layer 334 which is the movable electrode 246 as shown in Fig. The high-concentration p-type layer 344 is formed by depositing amorphous silicon in the same manner as the formation of the support layer 242, and then doping the dopant impurity at a high concentration by ion implantation.
38, an amorphous silicon layer 340 serving as the support layer 242 is deposited on the entire surface of the high-concentration p-type layer 344. Then, as shown in Fig. The method of forming the amorphous silicon layer 340 can be selected from various physical vapor deposition methods and chemical vapor deposition methods.
Next, as shown in Fig. 39, a reflection film 350 serving as a reflection layer 244 is formed on the entire surface of the amorphous silicon layer 340. [ The reflective film 350 can be formed of a metal material or a dielectric multilayer film. The method of forming the reflective film 350 can be selected from various physical vapor deposition methods and chemical vapor deposition methods. Further, the surface of the amorphous silicon layer 340 may be mirror-polished before the reflective film 350 is formed. Thus, the reflectance of the reflective film 350 can be improved.
Subsequently, as shown in Fig. 40, the fourth metal layer 334, the amorphous silicon layer 340, and the reflective film 350 are collectively trimmed. The trimming can be performed by a dry etching method such as plasma etching. As a result, the surface of the third sacrificial layer 313 is exposed in the vicinity of the edge of the fourth metal layer 334.
41, the sacrificial layer from the third sacrificial layer 313 to the first sacrificial layer 311 is removed, and the spatial light modulation element 203 is completed. Since the sacrificial layer from the third sacrificial layer 313 to the first sacrificial layer 311 is directly or indirectly continuous, it can be collectively removed by etching using gas or liquid.
In the spatial light modulation device 203 manufactured through the above process, a high-concentration p-type layer 344 is interposed at the interface between the amorphous silicon layer 340 and the movable electrode 246. Thereby, an ohmic junction is formed between the amorphous silicon layer 340 and the movable electrode 246.
When the amorphous silicon layer 340, which is a semiconductor, and the movable electrode 246 made of metal are in direct contact with each other, Schottky coupling is formed between them, and a rectifying effect is produced. However, when the ohmic junction is formed at the interface between the amorphous silicon layer 340 and the movable electrode 246, since the rectifying effect is not generated, the potential of the movable electrode 246 is stabilized and the response to the applied driving power Stable.
The spatial light modulation element 203 has a structure in which a high-concentration p-type layer 344 is formed on the entire interface between the amorphous silicon layer 340 and the movable electrode 246. However, when the high-concentration p-type layer 346 is formed in a part of the interface as in the case of the spatial light modulation device 204 shown in Fig. 42, an ohmic junction is formed between the amorphous silicon layer 340 and the movable electrode 246 So that the rectifying effect by the Schottky junction is invalidated. Therefore, even when the high-concentration p-type layer 346 is formed at a part of the interface between the amorphous silicon layer 340 and the movable electrode 246 by partial ion implantation, the same effect is produced.
The spatial light modulation elements 204 and 205 have the same structure as that of the spatial light modulation element 200 shown in FIG. 23 and the like, except that the high-concentration p-type layers 344 and 346 are provided. However, even in the case of the spatial light modulation device 201 shown in Fig. 30, the spatial light modulation device 202 shown in Fig. 36, and the like, the high concentration p-type layer 314 is formed at the interface between the amorphous silicon layer 340, The ohmic junction is formed by providing the ohmic contacts 344 and 346 so that the effect of rectifying the interface can be nullified and the reflective portion 240 can be made electrically stable. The high concentration p-type layer 344 and the high concentration p-type layer 346 may be formed by a structure different from that of the spatial light modulation elements 200, 201 and 202 using the gimbal part 230, for example, A structure that cancels the rectifying effect can be applied.
Fig. 43 is a schematic plan view of another spatial light modulation device 205. Fig. The spatial light modulation device 205 has the same structure as that of the spatial light modulation device 200 shown in Fig. 3 and the like, except for the following description. Therefore, the same reference numerals are assigned to common elements, and redundant explanations are omitted.
In the spatial light modulating element 205, the guttering portion 231 has a structure different from the guttering portion 230 of the spatial light modulation element 200. That is, the luggage compartment 231 includes a movable frame 236 directly supported from a pair of pillars 232 via a twist shaft portion 235, and a movable frame 236 supported from the movable frame 236 through a twist axis portion 237, (238).
This allows the space 231 of the spatial light modulation device 205 to be occupied by the surface of the substrate 210 rather than the space 220 of the spatial light modulation device 200 having the fixed frame 234 Small area. This makes it possible to increase the area of the fixed electrodes 212 and 214 arranged so as not to overlap with the gimbal portion 231 and to exert a large driving force on the movable electrode 246 of the reflecting portion 240.
In the spatial light modulation element 205, for example, when the reflecting portion 240 is oscillated with the twist axis portion 235 as a pivot axis, the spatial light modulation element 205 is moved from the two adjacent fixed electrodes 212, Power. As a result, the driving force applied to the movable electrode 246 becomes larger as compared with the case where the fixed electric power is applied by one fixed electrode.
44 is a schematic plan view of another spatial light modulating element 206. Fig. The spatial light modulating element 206 has the same structure as the spatial light modulating element 205 shown in Fig. 43 and the like, except for the portion described below. Therefore, the same reference numerals are assigned to common elements, and redundant explanations are omitted.
Since the movable frame 236 is supported from the strut 232 via the twisted shaft portion 237, the load portion 233 of the spatial light modulating element 206 is supported by the load 232 of the spatial light modulating element 205, (231). A pair of pillars 232 are arranged in parallel with the longitudinal direction of the shielding plate 222 and each of the warping shafts 235 and 237 is shielded Are arranged in a direction parallel to the longitudinal direction of the plate (222).
The distance between the fixed electrodes 212 and 214 disposed on the surface of the substrate 210 is not the diagonal of the substrate 210 but the center of each side of the rectangular area surrounded by the shield 220, As shown in Fig. As a result, the distance between the fixed electrodes 212 and 214 is shortened, and the effective area of the fixed electrode is increased.
The fixed electrodes 212 and 214 are disposed at the corners of the substrate 210 farthest from the center of swing of the oscillating portion 238 on the substrate 210. [ Therefore, the electrostatic force generated between the fixed electrodes 212, 214 and the movable electrode 246 efficiently drives the reflecting portion 240.
45 is a schematic diagram of the exposure apparatus 400. Fig. The exposure apparatus 400 includes an illumination light generating unit 500, an illumination optical system 600, and a projection optical system 700. The exposure apparatus 400 is provided with a spatial light modulator 100 and allows illumination light having an arbitrary illumination distribution to enter the illumination optical system 600 when the light source mask optimization method is executed.
The illumination light generating unit 500 includes a control unit 510, a light source 520, a spatial light modulator 100, a prism 530, an imaging optical system 540, a beam splitter 550, and a measurement unit 560. The light source 520 generates the illumination light L. The illumination light L generated by the light source 520 has an illuminance distribution according to the characteristics of the light emission mechanism of the light source 520. Therefore, the illumination light L has the original image I 1 on the cross section orthogonal to the optical path of the illumination light L.
The illumination light L emitted from the light source 520 is incident on the prism 530. The prism 530 guides the illumination light L to the spatial light modulator 100, and then exits the illumination light L to the outside. The spatial light modulator 100 modulates the incident illumination light L under the control of the control unit 510. The structure and operation of the spatial light modulator 100 have already been described.
The illumination light L emitted from the prism 530 through the spatial light modulator 100 is incident on the rear illumination optical system 600 via the imaging optical system 540. The imaging optical system 540 forms an illumination light image I 3 on the incident surface 612 of the illumination optical system 600.
The beam splitter 550 is disposed on the optical path of the illumination light L between the imaging optical system 540 and the illumination optical system. The beam splitter 550 separates a part of the illumination light L before it is incident on the illumination optical system 600 and guides it to the measurement unit 560.
The measurement unit 560 measures the image of the illumination light L at a position optically conjugate with the incident surface 612 of the illumination optical system 600. [ Thus, the measuring section 560 measures an image identical to the illumination light image I 3 incident on the illumination optical system 600. Accordingly, the control unit 510 can control the feedback of the spatial light modulator 100 with reference to the illumination light image I 3 measured by the measurement unit 560.
The illumination optical system 600 includes a fly-eye lens 610, a condenser optical system 620, a field stop 630, and an imaging optical system 640. At the emitting end of the illumination optical system 600, a mask stage 720 holding the mask 710 is disposed.
The fly-eye lens 610 has a plurality of lens elements densely arranged in parallel, and forms a secondary light source on the rear focal plane including the same number of illumination light images I 3 as the number of lens elements. The condenser optical system 620 condenses the illumination light L emitted from the fly-eye lens 610 to superimpose illumination of the field stop 630.
The illumination light L having passed through the field stop 630 forms an irradiation light image I 4 on the pattern surface of the mask 710 by the imaging optical system 640 as an image of the opening of the field stop 630. In this manner, the illumination optical system 600, the Koehler illumination by the pattern surface of the mask (710) disposed at the output end, the projected light image I 4.
The illuminance distribution formed at the incident end of the fly-eye lens 610, which is also the incident surface 612 of the illumination optical system 600, is an illuminance distribution of the entire secondary light source formed at the emitting end of the fly- Distribution and high correlation. The illumination light image I 3 incident on the illumination optical system 600 by the illumination light generating unit 500 is also reflected on the irradiation light image I 4 which is the illumination distribution of the illumination light L irradiated onto the mask 710 by the illumination optical system 600.
The projection optical system 700 is disposed immediately after the mask stage 720 and has an aperture diaphragm 730. The aperture stop 730 is disposed at a position optically conjugate with the emitting end of the fly's eye lens 610 of the illumination optical system 600. [ At the emitting end of the projection optical system 700, a substrate stage 820 holding a substrate 810 coated with a photosensitive material is disposed.
The mask 710 held on the mask stage 720 has a mask pattern composed of a region for reflecting or transmitting the illumination light L irradiated by the illumination optical system 600 and a region for absorbing the illumination light L. [ Therefore, by irradiating the illumination light image I 4 to the mask 710, a projection by the mask pattern and the illumination light of the illumination intensity distribution of the image interaction I 4 itself of the mask 710 honor the image I 5 is generated. Projection light image I 5 is projected onto the light-sensitive material of the substrate 810, thereby forming a resist layer having a desired pattern on a surface of the substrate 810.
Although the optical path of the illumination light L is linear in FIG. 44, the exposure apparatus 400 can be downsized by bending the optical path of the illumination light L. Although Fig. 44 shows that the illumination light L is transmitted through the mask 710, a reflection type mask 710 may be used.
46 is a partially enlarged view of the illumination light generating unit 500 and shows the role of the spatial light modulator 100 in the exposure apparatus 400. FIG. The prism 530 has a pair of reflecting surfaces 532 and 534. The illumination light L incident on the prism 530 is irradiated toward the spatial light modulator 100 by one of the reflection surfaces 532. [
As already described, the spatial light modulator 100 has a plurality of reflective portions 240 that can be individually swung. Therefore, the control unit 510 controls the spatial light modulator 100 to form an arbitrary light source image I 2 according to the demand.
The light source image I 2 emitted from the spatial light modulator 100 is reflected by the other reflecting surface 534 of the prism 530 and exits from the right end surface of the prism 530 in the figure. The light source image I 2 emitted from the prism 530 forms an illumination light image I 3 on the incident surface 612 of the illumination optical system 600 by the imaging optical system 540.
While the present invention has been described with reference to the embodiment, the technical scope of the present invention is not limited to the scope described in the above embodiment. It is apparent to those skilled in the art that various changes or improvements can be added to the above embodiments. It is apparent from the description of the claims that the form of such addition or improvement is included in the technical scope of the present invention.
The order of operations, steps, steps, and steps of the apparatus and the system shown in the patent scope, specification, and drawings are not specifically described as "before", "before", and the like, It can be realized in any order unless it is used in processing. In the claims, specification, and drawings, even if the description is made using "priority", "next", etc. for the sake of convenience, it does not mean that it is necessary to carry out in this order.
